tracing: Rename trace_buffer to array_buffer

As we are working to remove the generic "ring_buffer" name that is used by
both tracing and perf, the ring_buffer name for tracing will be renamed to
trace_buffer, and perf's ring buffer will be renamed to perf_buffer.

As there already exists a trace_buffer that is used by the trace_arrays, it
needs to be first renamed to array_buffer.

Link: https://lore.kernel.org/r/20191213153553.GE20583@krava

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

include/linux/trace_events.h

@@ -11,7 +11,7 @@
 #include <linux/tracepoint.h>
 
 struct trace_array;
-struct trace_buffer;
+struct array_buffer;
 struct tracer;
 struct dentry;
 struct bpf_prog;
@@ -79,7 +79,7 @@ struct trace_entry {
 struct trace_iterator {
 	struct trace_array	*tr;
 	struct tracer		*trace;
-	struct trace_buffer	*trace_buffer;
+	struct array_buffer	*array_buffer;
 	void			*private;
 	int			cpu_file;
 	struct mutex		mutex;

kernel/trace/blktrace.c

@@ -75,7 +75,7 @@ static void trace_note(struct blk_trace *bt, pid_t pid, int action,
 	ssize_t cgid_len = cgid ? sizeof(cgid) : 0;
 
 	if (blk_tracer) {
-		buffer = blk_tr->trace_buffer.buffer;
+		buffer = blk_tr->array_buffer.buffer;
 		pc = preempt_count();
 		event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
 						  sizeof(*t) + len + cgid_len,
@@ -248,7 +248,7 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
 	if (blk_tracer) {
 		tracing_record_cmdline(current);
 
-		buffer = blk_tr->trace_buffer.buffer;
+		buffer = blk_tr->array_buffer.buffer;
 		pc = preempt_count();
 		event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
 						  sizeof(*t) + pdu_len + cgid_len,

kernel/trace/ftrace.c

@@ -146,7 +146,7 @@ static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
 {
 	struct trace_array *tr = op->private;
 
-	if (tr && this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid))
+	if (tr && this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid))
 		return;
 
 	op->saved_func(ip, parent_ip, op, regs);
@@ -6922,7 +6922,7 @@ ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
 
 	pid_list = rcu_dereference_sched(tr->function_pids);
 
-	this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
+	this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
 		       trace_ignore_this_task(pid_list, next));
 }
 
@@ -6976,7 +6976,7 @@ static void clear_ftrace_pids(struct trace_array *tr)
 	unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
 
 	for_each_possible_cpu(cpu)
-		per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false;
+		per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = false;
 
 	rcu_assign_pointer(tr->function_pids, NULL);
 
@@ -7100,7 +7100,7 @@ static void ignore_task_cpu(void *data)
 	pid_list = rcu_dereference_protected(tr->function_pids,
 					     mutex_is_locked(&ftrace_lock));
 
-	this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
+	this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
 		       trace_ignore_this_task(pid_list, current));
 }